Why not just make another attack mode for each weapon. So it'll be Single, Burst, and Eyeshot. And remove that stupid ammo requirement for guns. You already have a gun, so why should you bother getting ammo, reloading and shit. And while we're on the topic, let's add a Redeemer to the game, spawning every 24 hours in a random place so people can remote-nuke others for the lulz.
Aimed shots are already quite powerful, so making them easier to do will only cause people to die faster.